High-efficiency gene knockdown using chimeric ribozymes in fish embryos

We report an effective gene knockdown technique in rainbow trout embryos using additional RNA components combined with ribozymes (Rzs). Chimeric Rzs (tRzCs) containing tRNAVal, Rz against GFP, and a constitutive transport element were microinjected into transgenic embryos. tRzCs induced greater gene interference than Rzs alone. Control tRzCs did not affect unpaired bases of target RNA, and the tRzC did not interfere with non-relevant gene expression, suggesting that the tRzC-mediated gene-interference effects were sequence-specific. Furthermore, the tRzC-containing expression vector specifically suppressed target GFP expression in transgenic trout. tRzCs enhance Rz cleavage and could therefore be powerful tools for studying unknown gene function in vertebrates.